DE2947166C1 - Method and device for connecting thermoplastic pipe elements - Google Patents

Method and device for connecting thermoplastic pipe elements

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Publication number
DE2947166C1
DE2947166C1 DE2947166A DE2947166A DE2947166C1 DE 2947166 C1 DE2947166 C1 DE 2947166C1 DE 2947166 A DE2947166 A DE 2947166A DE 2947166 A DE2947166 A DE 2947166A DE 2947166 C1 DE2947166 C1 DE 2947166C1
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DE
Germany
Prior art keywords
welding
circuit
time
preheating
sleeve
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Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
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DE2947166A
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German (de)
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DE2947166D2 (en
Inventor
Werner Sturm
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Individual
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Individual
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
    • F16L47/00—Connecting arrangements or other fittings specially adapted to be made of plastics or to be used with pipes made of plastics
    • F16L47/02—Welded joints; Adhesive joints
    • F16L47/03—Welded joints with an electrical resistance incorporated in the joint
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3404—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint
    • B29C65/342—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the type of heated elements which remain in the joint comprising at least a single wire, e.g. in the form of a winding
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C65/00—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor
    • B29C65/02—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure
    • B29C65/34—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement"
    • B29C65/3472—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint
    • B29C65/3476—Joining or sealing of preformed parts, e.g. welding of plastics materials; Apparatus therefor by heating, with or without pressure using heated elements which remain in the joint, e.g. "verlorenes Schweisselement" characterised by the composition of the heated elements which remain in the joint being metallic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/01—General aspects dealing with the joint area or with the area to be joined
    • B29C66/02—Preparation of the material, in the area to be joined, prior to joining or welding
    • B29C66/024—Thermal pre-treatments
    • B29C66/0242—Heating, or preheating, e.g. drying
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5221—Joining tubular articles for forming coaxial connections, i.e. the tubular articles to be joined forming a zero angle relative to each other
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/50—General aspects of joining tubular articles; General aspects of joining long products, i.e. bars or profiled elements; General aspects of joining single elements to tubular articles, hollow articles or bars; General aspects of joining several hollow-preforms to form hollow or tubular articles
    • B29C66/51—Joining tubular articles, profiled elements or bars; Joining single elements to tubular articles, hollow articles or bars; Joining several hollow-preforms to form hollow or tubular articles
    • B29C66/52—Joining tubular articles, bars or profiled elements
    • B29C66/522—Joining tubular articles
    • B29C66/5229—Joining tubular articles involving the use of a socket
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
    • B29C66/9161—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux
    • B29C66/91641—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux the heat or the thermal flux being non-constant over time
    • B29C66/91643—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux the heat or the thermal flux being non-constant over time following a heat-time profile
    • B29C66/91645—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux the heat or the thermal flux being non-constant over time following a heat-time profile by steps
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/91—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux
    • B29C66/914—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux
    • B29C66/9161—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux
    • B29C66/91651—Measuring or controlling the joining process by measuring or controlling the temperature, the heat or the thermal flux by controlling or regulating the temperature, the heat or the thermal flux by controlling or regulating the heat or the thermal flux, i.e. the heat flux by controlling or regulating the heat generated by Joule heating or induction heating
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/94—Measuring or controlling the joining process by measuring or controlling the time
    • B29C66/944—Measuring or controlling the joining process by measuring or controlling the time by controlling or regulating the time
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/80—General aspects of machine operations or constructions and parts thereof
    • B29C66/87—Auxiliary operations or devices
    • B29C66/874—Safety measures or devices
    • B29C66/8748—Safety measures or devices involving the use of warnings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/94—Measuring or controlling the joining process by measuring or controlling the time
    • B29C66/949—Measuring or controlling the joining process by measuring or controlling the time characterised by specific time values or ranges
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C66/00—General aspects of processes or apparatus for joining preformed parts
    • B29C66/90—Measuring or controlling the joining process
    • B29C66/96—Measuring or controlling the joining process characterised by the method for implementing the controlling of the joining process
    • B29C66/967—Measuring or controlling the joining process characterised by the method for implementing the controlling of the joining process involving special data inputs or special data outputs, e.g. for monitoring purposes
    • B29C66/9674—Measuring or controlling the joining process characterised by the method for implementing the controlling of the joining process involving special data inputs or special data outputs, e.g. for monitoring purposes involving special data outputs, e.g. special data display means

Description

Die Erfindung betrifft ein Verfahren zum Verbinden thermopla­ stischer Leitungselemente nach dem Oberbegriff des Anspruches 1, wie es aus der CH-PS 3 98 957 bekannt geworden ist, und be­ zieht sich ferner auf ein Gerät zum Durchführen des Verfah­ rens.The invention relates to a method for connecting thermopla stischer line elements according to the preamble of the claim 1, as is known from CH-PS 3 98 957, and be also extends to a device for performing the procedure rens.

Beim Verbinden von thermoplastischen Leitungselementen, das heißt von Rohrstücken, Formstücken und Schaltmitteln, zum Beispiel Ventilen, ist es bekannt, die zum Verbinden solcher Elemente erforderliche Schweißwärme durch elektrische Wider­ standsheizung zu erzeugen. Hierbei ist es bekannt, in den Verbindungen, zum Beispiel in Muffenenden oder in separaten Muffen, in der Nähe der Verbindungsflächen einen strombeauf­ schlagten Leiter anzuordnen, durch dessen Erwärmung die Ver­ bindungsstelle in schweißfähigen Zustand gebracht wird. Beim Verbinden der Enden von Leitungselementen durch von diesen getrennte Muffen ist der strombeschickte Leiter meistens eine Wicklung aus einem Widerstandsheizdraht, dessen Windungen mit Abstand voneinander in der Nähe der Innenwandung des Muffen­ körpers angeordnet sind. Beim Stromdurchgang durch die Wick­ lung werden die innenwandige Partie der Muffe und ebenso die den Leitungselementen benachbarten Teile in bindungsfähigen Zustand gebracht und dadurch miteinander verschweißt, ohne daß an der Verbindungsstelle Deformationen der Teile, das heißt der Enden der Leitungselemente und des Muffenkörpers, auftreten. Das Anwendungsgebiet der erwähnten, als Elektro- Schweißmuffen bezeichneten Muffen hat sich seit ihrer Ein­ führung ständig erweitert und umfaßt heute alle gängigen Durchmesserbereiche. Es hat sich aber gezeigt, daß bei größer werdenden Rohrdurchmessern, zum Beispiel für Nennweiten 160 bis 400, Probleme auftreten, die sich bei kleineren Nennwei­ ten nicht oder nur wenig auswirken.When connecting thermoplastic pipe elements, the means of pipe pieces, fittings and switching means, for Example valves, it is known to connect such Elements required welding heat through electrical resistance to produce auxiliary heating. Here it is known in the Connections, for example in socket ends or in separate Socket a current on near the connection surfaces suggested conductors, by heating the ver binding point is brought into a weldable state. At the Connect the ends of pipe elements by them separate sleeves, the current-fed conductor is usually one Winding from a resistance heating wire, whose turns with Distance from each other near the inner wall of the sleeves  body are arranged. When passing current through the wick the inner wall part of the sleeve and also the parts adjacent to the line elements in binding Condition brought and thus welded together, without that at the junction deformations of the parts, the is called the ends of the pipe elements and the socket body, occur. The field of application of the mentioned, as electrical Welded sleeves designated sleeves have been on since their on leadership is constantly expanding and now includes all common Diameter ranges. However, it has been shown that larger pipe diameters, for example for nominal widths 160 up to 400, problems occur that occur with smaller nominal sizes have little or no impact.

Elektro-Schweißmuffen für die genannten größeren Nennweiten werden aus einem rohrförmigen Muffenkörper hergestellt, der zunächst unter Erwärmung aufgeweitet wird und dadurch eine Schrumpfreserve erhält, die, an der Verbindungsstelle durch den Schweißvorgang ausgelöst, die Überbrückung des sich durch Durchmesserdifferenzen ergebenden Spiels bewirkt und das Auf­ pressen des Muffenkörpers auf die Enden der Leitungselemente sicherstellt. Die meistens monofile Wicklung aus einem Wider­ standsheizdraht wird im aufgeweiteten Zustand des Muffenkör­ pers in diesen eingebracht und mit diesem verbunden. Es fin­ det aber bereits während der Lagerung, das heißt im kalten Zustand, eine gewisse Rückbildung der Schrumpfreserve statt, was durch eine entsprechend größere Aufweitung des Muffenkör­ pers berücksichtigt wird. Der in den Muffenkörper eingebrach­ te Widerstandsheizdraht wird somit schon bei der Lagerung der Elektro-Schweißmuffen durch das Schrumpfen des Muffenkörpers einer Druckbeanspruchung unterworfen. Da jedoch der Wider­ standsheizdraht im thermoplastischen Material eingebettet ist, werden die einzelnen Windungen entsprechend der wirksa­ men Druckspannung verkürzt. Wird nun für die Herstellung ei­ ner Schweißverbindung der Widerstandsheizdraht einer solchen Schweißmuffe mit elektrischem Strom beschickt, fällt die vom Muffenkörpermaterial ausgeübte Stützwirkung weg, und es kann vorkommen, daß zwei benachbarte Windungen des Widerstands­ heizdrahtes sich metallisch berühren.Electric welding sleeves for the larger nominal widths mentioned are made from a tubular sleeve body that is first expanded with heating and thereby one Shrink reserve, which, at the junction through triggered the welding process, bridging itself through Diameter differences resulting game causes and the Auf press the sleeve body onto the ends of the pipe elements ensures. Mostly monofilament winding from one counter auxiliary heating wire is in the expanded state of the socket body pers introduced into this and connected with it. It fin detects already during storage, i.e. in the cold Condition, a certain regression of the shrink reserve instead, what by a correspondingly larger expansion of the socket body pers is taken into account. Who broke into the socket body te resistance heating wire is thus already in the storage of Electric welding sleeves due to the shrinking of the sleeve body subjected to a pressure load. However, since the cons auxiliary heating wire embedded in the thermoplastic material is, the individual turns according to the effective compressive stress is reduced. Will now egg for the production  ner welded connection of the resistance heating wire of such When the welding sleeve is supplied with electrical current, it falls from the Sleeve body material exerted support, and it can occur that two adjacent turns of resistance heating wire touch metallic.

In gleichem Sinne wirkt beim Schweißvorgang die durch den An­ stieg der Temperatur verursachte Ausdehnung des Widerstands­ heizdrahtes, die zu einer wesentlichen Verlängerung desselben führt. Die durch die Schweißwärme ausgelöste Schrumpfreserve des Muffenkörpers und die gleichzeitig auftretende Verlänge­ rung des Widerstandsheizdrahtes führen dazu, daß einzelne Windungen seitlich ausweichen, da zwischen den Windungen das thermoplastische Material am stärksten erwärmt wird und dort am fließfähigsten ist. Wie bereits erwähnt wurde, wirken sich die beiden Faktoren Schrumpfreserve und Drahtausdehnung bei Schweißmuffen für große Nennweiten stärker aus und können dort eher zu Störungen führen als bei Schweißmuffen für klei­ ne Nennweiten. Selbst wenn auch die beim Lagern auftretende Schrumpfung durch einen zusätzlichen Aufwand vermieden werden könnte, zum Beispiel durch Aufsetzen der Muffe auf einen me­ tallischen Zylinder, der das Schrumpfen verhindert, so bliebe trotzdem die durch die Erwärmung auftretende Verlängerung des Widerstandsheizdrahtes bestehen und damit die Möglichkeit ei­ nes Kurzschlusses benachbarter Windungen, was zu erhöhter Stromaufnahme und zur Beeinträchtigung der Verschweißung führt.In the same sense, the welding process is affected by the on the temperature rose caused the resistance to expand heating wire leading to a substantial extension of the same leads. The shrink reserve triggered by the heat of welding of the socket body and the simultaneously occurring extensions tion of the resistance heating wire cause individual Dodge turns laterally, because between the turns thermoplastic material is most heated and there is the most fluid. As already mentioned, have an effect the two factors of shrink reserve and wire expansion Welding sleeves for large nominal widths are stronger and can there are more likely to cause faults than with welding sockets for small parts ne nominal sizes. Even if the one that occurs during storage Shrinkage can be avoided by additional effort could, for example by placing the sleeve on a me metallic cylinder, which prevents shrinkage, would remain nevertheless the extension of the Resistance heating wire exist and thus the possibility short circuit of adjacent turns, resulting in increased Current consumption and to impair the welding leads.

Aus der DE-AS 10 82 042 ist es ferner bekannt, zum Schweißen von Kunststoff, insbesondere zum Verschweißen von Kunststoff- Folien, mittels zweier parallelgeschalteter Stromkreise vor dem eigentlichen Stromimpuls zum Verschweißen einen kurzen Stromstoß mit niedrigerer Stromstärke zum Vorwärmen auf die vorhandenen Heizleiter zu geben. Hierbei tritt jedoch notwen­ digerweise eine, wenn auch nur kurze Unterbrechung zwischen den Stromimpulsen auf, und außerdem sind zwei getrennte Stromkreise für die Vorwärmung des Heizleiters und für die eigentliche Schweißung erforderlich. Bei einer ringförmigen Anordnung der Heizleiter für die Folienschweißung ergibt sich nicht das Problem eines Kurzschlusses infolge Wärmedehnung des Heizleiters.From DE-AS 10 82 042 it is also known for welding of plastic, especially for welding plastic Foils, using two circuits connected in parallel the actual current pulse for welding a short Current surge with lower current for preheating to the to give existing heating conductors. However, this is necessary  a break, albeit brief, between the current pulses, and there are also two separate ones Circuits for preheating the heating conductor and for the actual welding required. With an annular The arrangement of the heating conductors for the foil welding results not the problem of a short circuit due to thermal expansion of the heating conductor.

Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren der eingangs beschriebenen Art so auszugestalten, daß beim Ver­ binden thermoplastischer Leitungselemente mit Hilfe einer Elektro-Schweißmuffe eine gegenseitige Berührung der Windun­ gen ihrer Heizwicklung mit Sicherheit vermieden wird.The invention has for its object a method of type described above so that when ver bind thermoplastic pipe elements with the help of a Electric welding sleeve a mutual contact of the windun against their heating winding is definitely avoided.

Diese Aufgabe wird gemäß der Erfindung dadurch gelöst, daß die gesamte Schweißzeit in zwei Teilzeiten mit der ersten Teilzeit als Vorwärmzeit und der zweiten Teilzeit als Schweißzeit unterteilt wird, wobei die erste und die zweite Teilzeit direkt nacheinander folgen, daß während der Vorwärm­ zeit nur ein Bruchteil der Nennleistung der Schweißleistung zugeführt wird, und daß die zum Schweißen erforderliche Nenn­ schweißleistung durch Überbrücken eines Vorwärmschaltkreises zugeführt wird.This object is achieved according to the invention in that the entire welding time in two part times with the first Part time as preheating and the second part time as Welding time is divided, the first and the second Follow part-time in succession that during preheating only a fraction of the nominal output of the welding output is supplied, and that the nominal required for welding welding performance by bridging a preheating circuit is fed.

Das Verfahren erlaubt auf verhältnismäßig einfache Weise, die vor allem bei Elektro-Schweißmuffen größeren Durchmessers auftretenden Probleme wirksam zu beherrschen, wodurch ein­ wandfreie Verschweißungen erreicht werden. Es können Vorwärm­ zeiten für die Nennweiten 160 bis 400 von etwa ein bis zehn Minuten vorgesehen werden.The procedure allows, in a relatively simple way, the especially with larger diameter electric welding sleeves to effectively master the problems that arise, thereby wall-free welds can be achieved. It can preheat times for nominal sizes 160 to 400 from about one to ten Minutes can be provided.

Das erfindungsgemäße Verfahren wird mittels eines Gerätes durchgeführt mit einem einen Schweißstromkreis nach Zufuhr der Gesamtschweißleistung unterbrechenden Gesamtzeitschalt­ kreis, das dadurch gekennzeichnet ist, daß der Schweißstrom­ kreis einen mit einer Diode versehenen Vorwärmschaltkreis und eine dazu parallelgeschaltete Schaltstufe aufweist, wobei der Vorwärmschaltkreis nach Ablauf einer Vorwärmzeit zur Umschal­ tung des Schweißstromkreises auf Nennschweißleistung durch die Schaltstufe überbrückbar ist.The method according to the invention is by means of a device performed with a welding circuit after feeding of the total welding power interrupting total time switch  circle, which is characterized in that the welding current circuit a preheating circuit provided with a diode and has a switching stage connected in parallel, the Preheating circuit after a preheating time for switching the welding circuit to the nominal welding power the switching stage can be bridged.

Ein solches Gerät mit einer Diode im Vorwärmschaltkreis hat eine sehr geringe Verlustleistung, so daß leichte und handli­ che Geräte entwickelt werden können, was insofern sehr wich­ tig ist, als solche Muffenschweißgeräte auf Baustellen vor Ort eingesetzt werden und daher nicht zu schwer und unhand­ lich sein dürfen.Such a device with a diode in the preheating circuit has a very low power loss, so that light and handy Che devices can be developed, which was very important is, as such socket welders on construction sites Place used and therefore not too heavy and unwieldy may be.

Die Erfindung ist in der Zeichnung in einem Ausführungsbei­ spiel dargestellt und nachfolgend beschrieben. Die einzige Figur zeigt die schematische Darstellung des Schweißgerätes.The invention is in one embodiment in the drawing game shown and described below. The only Figure shows the schematic representation of the welding device.

In der Figur ist ein Netzanschluß 1 dargestellt, der zum An­ schluß eines Schweißgerätes 4 zum Herstellen von Verbindungs­ stellen an thermoplastischen Leitungselementen mittels einer Elektro-Schweißmuffe 15 dient. Die Elektro-Schweißmuffe 15 ist über einen Schweißstromkreis 2 mit dem Netzanschluß 1 verbunden.In the figure, a network connection 1 is shown, which serves to connect to a welding device 4 for making connections to thermoplastic line elements by means of an electric welding sleeve 15 . The electric welding sleeve 15 is connected to the mains connection 1 via a welding circuit 2 .

Vom Schweißstromkreis 2 zweigt eine Speiseleitung 3 zu einem nicht dargestellten Netzteil ab, durch den eine Kleinspannung zur Versorgung der Regel-, Steuer- und Meßmittel 13 des Gerä­ tes 4 erzeugt wird. Als Schweißgerät 4 kann ein bekanntes Elektro-Schweißgerät verwendet werden, welches die Heizener­ gie für die Elektro-Schweißmuffe 15 dosiert, und zwar zum Beispiel über eine Stromregelung mit Zeitschaltkreis (CH-PS 3 98 957) oder mit einem geregelten Integrationskreis aus Strom und Zeit (CH-PS 5 23 130). From the welding circuit 2 , a feed line 3 branches off to a power supply unit, not shown, through which a low voltage for supplying the regulating, control and measuring means 13 of the device 4 is generated. As a welding device 4 , a known electric welding device can be used, which doses the heating energy for the electric welding sleeve 15 , for example via a current control with a timer circuit (CH-PS 3 98 957) or with a regulated integration circuit of current and time (CH-PS 5 23 130).

Wie aus der Figur ersichtlich ist, weist das Elektro-Schweiß­ gerät zwei Zeitschaltkreise auf, einen Gesamtzeitschaltkreis 5, der die der Elektro-Schweißmuffe 15 zuzuführende Heizener­ gie dosiert und nach Erreichen des Sollwertes durch eine Schaltstufe 9 den Schweißstromkreis 2 unterbricht, und einen zusätzlichen, als Vorwärmschaltkreis 6 bezeichneten Zeit­ schaltkreis, der nach einer als Vorwärmzeit bezeichneten Zeitdauer eine im Schweißstromkreis 2 liegende Diode 8 mit einer Schaltstufe 10 überbrückt. Durch diese Anordnung ist es möglich, der Elektro-Schweißmuffe 15 während der Vorwärmzeit eine kleinere Spannung anzubieten, so daß die Temperatur des Heizdrahtes nur unwesentlich über derjenigen des Fließpunktes des thermoplastischen Materials des Muffenkörpers liegt. Geht man davon aus, daß die Schweißleistung dem öffentlichen Wech­ selstromnetz entnommen wird, so erfolgt während der Vorwärm­ zeit der Schweißvorgang mit der halben Leistung. Es ist je­ doch auch möglich, die Teilleistung in anderer Weise zu steu­ ern, zum Beispiel stufenweise oder kontinuierlich.As can be seen from the figure, the electric welder two timing circuits to a total time circuit 5, the electric welding sleeve 15 to be supplied Heizener energy metered and after reaching the desired value interrupts by a switching stage 9 the welding current circuit 2, and an additional, referred to as preheating circuit 6 time circuit, which bridges a lying in the welding circuit 2 diode 8 with a switching stage 10 after a period referred to as preheating time. By this arrangement, it is possible to offer the electric welding sleeve 15 during the preheating a smaller voltage, so that the temperature of the heating wire only slightly above that of the yield point is the thermoplastic material of the sleeve body. Assuming that the welding power is taken from the public AC network, the welding process takes place at half the power during the preheating time. However, it is also possible to control the partial power in a different way, for example step by step or continuously.

Dadurch, daß während der Vorwärmzeit nur eine Teilleistung für die Erwärmung der Elektro-Schweißmuffe 15 zur Verfügung steht, wird erreicht, daß die Ausdehnung des Heizdrahtes ent­ sprechend kleiner ist. Wegen der langsameren Erwärmung wäh­ rend der Vorwärmzeit ist die Fließfähigkeit des die Heiz­ drahtwicklung umgebenden Materials gleichmäßiger, ohne daß sich die Windungen der Heizdrahtwicklung radial aufweiten können. Auch erfolgt die Auslösung der Schrumpfreserve des Muffenkörpers langsamer, so daß die Aufwärmung des thermo­ plastischen Materials und das Schrumpfen des Muffenkörpers so langsam erfolgen, daß die einzelnen Windungen der Heizdraht­ wicklung sich nicht seitlich, sondern nur radial ausdehnen.Characterized in that only a partial power for heating the electric welding sleeve 15 is available during the preheating time, it is achieved that the expansion of the heating wire is accordingly smaller. Because of the slower heating during the preheating time, the fluidity of the material surrounding the heating wire winding is more uniform without the windings of the heating wire winding being able to expand radially. Also, the triggering of the shrink reserve of the sleeve body is slower, so that the heating of the thermoplastic material and the shrinking of the sleeve body take place so slowly that the individual turns of the heating wire winding do not expand laterally, but only radially.

Die für die Herstellung einer Verbindung mittels einer Elektro-Schweißmuffe erforderliche Gesamtschweißzeit setzt sich demnach aus einer Vorwärmzeit und der eigentlichen Schweißzeit zusammen. Die Vorwärmzeit wird zweckmäßig mittels eines Zählers mit Vorsignal bestimmt. Ist das Vorsignal er­ reicht, wird über die Schaltstufe 10 die der Elektro-Schweiß­ muffe 15 vorgeschaltete Diode 8 überbrückt.The total welding time required to establish a connection by means of an electric welding sleeve therefore consists of a preheating time and the actual welding time. The preheating time is expediently determined using a counter with a distant signal. If the distant signal is sufficient, the switching stage 10 bridges the diode 8 connected upstream of the electrical welding sleeve 15 .

Die Inbetriebnahme des Gerätes 4 erfolgt durch einen Start­ kreis 7, durch den über den Gesamtzeitschaltkreis 5 die Schaltstufe 9 eingeschaltet wird, womit die Vorwärmzeit be­ ginnt. Nach Erreichen des Vorsignals des Vorwärmschaltkreises wird die Diode 8 überbrückt und es beginnt die Schweißzeit, nach Ablauf welcher der Gesamtzeitschaltkreis 5 mit Hilfe der Schaltstufe 9 den Schweißstromkreis 2 unterbicht. Durch zum Beispiel optische Anzeigemittel 11, 12 wird die Art des Be­ triebszustandes angezeigt, das heißt das Vorwärmen und das Schweißen.The commissioning of the device 4 is carried out by a starting circuit 7 , through which the switching stage 9 is switched on via the total time circuit 5 , whereby the preheating time begins. After the pre-signal of the preheating circuit has been reached, the diode 8 is bridged and the welding time begins, after which the total time circuit 5 interrupts the welding circuit 2 with the aid of the switching stage 9 . The type of operating state is indicated by, for example, optical display means 11 , 12 , that is to say the preheating and the welding.

Claims (2)

1. Verfahren zum Verbinden thermoplastischer Leitungs­ elemente mit Hilfe einer eine Wicklung aus einem elek­ trischen Widerstandsdraht aufweisenden Muffe, wobei nach Anschluß an eine elektrische Stromquelle Wärme in der Wicklung erzeugt und nach Zuführen einer bestimmten Schweißleistung die Muffe mit den Leitungselementen ver­ schweißt wird, dadurch gekennzeich­ net, daß die gesamte Schweißzeit in zwei Teilzeiten mit der ersten Teilzeit als Vorwärmzeit und der zweiten Teilzeit als Schweißzeit unterteilt wird, wobei die erste und die zweite Teilzeit direkt nacheinander fol­ gen, daß während der Vorwärmzeit nur ein Bruchteil der Nennleistung der Schweißleistung zugeführt wird, und daß die zum Schweißen erforderliche Nennschweißleistung durch Überbrücken eines Vorwärmschaltkreises zugeführt wird. 1. A method of connecting thermoplastic line elements with the aid of a sleeve having a winding made of an electrical resistance wire, whereby heat is generated in the winding after connection to an electrical power source and the sleeve is welded to the line elements after supplying a specific welding power, characterized in that net that the entire welding time is divided into two part times with the first part time as preheating time and the second part time as welding time, the first and second part times following one after the other that only a fraction of the nominal power of the welding power is supplied during the preheating time, and that the nominal welding power required for welding is supplied by bridging a preheating circuit. 2. Gerät zum Durchführen des Verfahrens nach Anspruch 1 mit einem einen Schweißstromkreis nach Zufuhr der Gesamt­ schweißleistung unterbrechenden Gesamtzeitschaltkreis, dadurch gekennzeichnet, daß der Schweißstromkreis einen mit einer Diode (8) versehenen Vorwärmschaltkreis und eine dazu parallel geschaltete Schaltstufe (10) aufweist, wobei der Vorwärmschaltkreis nach Ablauf einer Vorwärmzeit zur Umschaltung des Schweißstromkreises auf Nennschweißleistung durch die Schaltstufe überbrückbar ist.2. Apparatus for performing the method according to claim 1 with a welding circuit interrupting the total welding power interrupting total time circuit, characterized in that the welding circuit has a diode ( 8 ) provided preheating circuit and a switching circuit ( 10 ) connected in parallel, the Preheating circuit after a preheating time for switching the welding circuit to the nominal welding power can be bridged by the switching stage.
DE2947166A 1978-04-28 1979-04-26 Method and device for connecting thermoplastic pipe elements Expired DE2947166C1 (en)

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CH469678A CH627962A5 (en) 1978-04-28 1978-04-28 METHOD AND DEVICE FOR CONNECTING THERMOPLASTIC LINE ELEMENTS.

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DE19792947166 Expired DE2947166D2 (en) 1978-04-28 1979-04-26 Method and apparatus for connecting thermoplastic conductor elements

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EP (1) EP0014716B1 (en)
JP (1) JPS55500239A (en)
AT (1) AT361748B (en)
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DE (2) DE2947166C1 (en)
GB (1) GB2036474B (en)
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SE7909894L (en) 1979-11-30
WO1979001000A1 (en) 1979-11-29
AT361748B (en) 1981-03-25
GB2036474A (en) 1980-06-25
IT1112586B (en) 1986-01-20
SE416386B (en) 1980-12-22
EP0014716B1 (en) 1982-07-14
GB2036474B (en) 1982-06-16
DE2947166D2 (en) 1980-11-13
ATA901079A (en) 1980-08-15
CH627962A5 (en) 1982-02-15
JPS55500239A (en) 1980-04-24
EP0014716A1 (en) 1980-09-03
US4334146A (en) 1982-06-08
IT7922231A0 (en) 1979-04-27

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